No … I think you must not have followed me, so I’ll spell it out in more detail.
Let’s imagine that there’s a species of AlphaZero-chess agents, with a heritable and variable reward function but identical in every other way. One individual might have a reward function of “1 for checkmate”, but another might have “1 for checkmate plus 0.1 for each enemy piece on the right side of the endgame board” or “1 for checkmate minus 0.2 for each enemy pawn that you’ve captured”, or “0 for checkmate but 1 for capturing the enemy queen”, or whatever.
Then every one of these individuals separately grows into “adults” by undergoing the “life experience” of the AlphaZero self-play training regime for 40,000,000 games. And now we look at the behavior of those “adults”.
If you take two identical twin adults in this species, you’ll find that they behave extremely similarly. If one tends to draw out the enemy bishop in thus-and-such situation, then so does the other. Why? Because drawing out the enemy bishop is useful given a certain kind of reward function, and they have the same reward function, and they’re both quite good at maximizing it. So you would find high broad-sense heritability of behavior.
But it’s unlikely that you’ll find a linear map from the space of reward functions to the space of midgame behavioral tendencies. Lots of individuals will be trying to draw out the enemy bishop in such-and-such situation, and lots of individuals won’t be trying to draw out the enemy bishop in that same kind of situation, for lots of different reasons, ultimately related to their different reward functions. The midgame behavior is more-or-less a deterministic function of the reward function, but it’s a highly nonlinear function. So you would measure almost zero narrow-sense heritability of behavior.
Wait a minute. Does your theory predict that heritability estimates about personality traits derived from MZTwins will be much much higher than estimates derived from DZTwins or other methods not involving MZTwins?
Yeah, one of the tell-tale signs of non-additive genetic influences is that MZ twins are still extremely similar, but DZ twins and more distant relatives are more different than you’d otherwise expect. (This connects to PGSs because PGSs are derived from distantly-related people.) See §1.5.5 here, and also §4.4 (including the collapsible box) for some examples.
Mkay.… I’m gonna tap out for now, but this is very helpful, thanks. I’m still pretty skeptical, though indeed
I am failing (and then I think later succeeding) at significant chunks of basic reading comprehension about what you’re saying;
I’m still confused, so my skepticism isn’t a confident No.
As a bookmark/trailhead, I suggest that maybe your theory of “personality has a high complexity but pretty deterministic map from a smallish number of pretty-genetically-linear full-brain-settings to behavior due to convergent instrumentality” and some sort of “personality mysteriously has a bunch of k-th order epistases that all add up” would both predict MZ being more similar than DZ, but your theory would predict this effect more strongly than the k-th order thing.
Another: there’s something weird where I don’t feel your argument about a complex map being deterministic because of convergent instrumentality ought to work for the sorts of things that personality traits are; like they don’t seem analogous to “draws out bishop in xyz position”, and in the chess example idk if I especially would there to be “personality traits” of play.… or something about this.
Another bookmark: IIUC your theory requires that the relevant underlying brain factors are extremeley pinned down by genetics, because the complicated map from underlying brain stuff to personality is chaotic.
No … I think you must not have followed me, so I’ll spell it out in more detail.
Let’s imagine that there’s a species of AlphaZero-chess agents, with a heritable and variable reward function but identical in every other way. One individual might have a reward function of “1 for checkmate”, but another might have “1 for checkmate plus 0.1 for each enemy piece on the right side of the endgame board” or “1 for checkmate minus 0.2 for each enemy pawn that you’ve captured”, or “0 for checkmate but 1 for capturing the enemy queen”, or whatever.
Then every one of these individuals separately grows into “adults” by undergoing the “life experience” of the AlphaZero self-play training regime for 40,000,000 games. And now we look at the behavior of those “adults”.
If you take two identical twin adults in this species, you’ll find that they behave extremely similarly. If one tends to draw out the enemy bishop in thus-and-such situation, then so does the other. Why? Because drawing out the enemy bishop is useful given a certain kind of reward function, and they have the same reward function, and they’re both quite good at maximizing it. So you would find high broad-sense heritability of behavior.
But it’s unlikely that you’ll find a linear map from the space of reward functions to the space of midgame behavioral tendencies. Lots of individuals will be trying to draw out the enemy bishop in such-and-such situation, and lots of individuals won’t be trying to draw out the enemy bishop in that same kind of situation, for lots of different reasons, ultimately related to their different reward functions. The midgame behavior is more-or-less a deterministic function of the reward function, but it’s a highly nonlinear function. So you would measure almost zero narrow-sense heritability of behavior.
Wait a minute. Does your theory predict that heritability estimates about personality traits derived from MZTwins will be much much higher than estimates derived from DZTwins or other methods not involving MZTwins?
Yeah, one of the tell-tale signs of non-additive genetic influences is that MZ twins are still extremely similar, but DZ twins and more distant relatives are more different than you’d otherwise expect. (This connects to PGSs because PGSs are derived from distantly-related people.) See §1.5.5 here, and also §4.4 (including the collapsible box) for some examples.
Mkay.… I’m gonna tap out for now, but this is very helpful, thanks. I’m still pretty skeptical, though indeed
I am failing (and then I think later succeeding) at significant chunks of basic reading comprehension about what you’re saying;
I’m still confused, so my skepticism isn’t a confident No.
As a bookmark/trailhead, I suggest that maybe your theory of “personality has a high complexity but pretty deterministic map from a smallish number of pretty-genetically-linear full-brain-settings to behavior due to convergent instrumentality” and some sort of “personality mysteriously has a bunch of k-th order epistases that all add up” would both predict MZ being more similar than DZ, but your theory would predict this effect more strongly than the k-th order thing.
Another: there’s something weird where I don’t feel your argument about a complex map being deterministic because of convergent instrumentality ought to work for the sorts of things that personality traits are; like they don’t seem analogous to “draws out bishop in xyz position”, and in the chess example idk if I especially would there to be “personality traits” of play.… or something about this.
Another bookmark: IIUC your theory requires that the relevant underlying brain factors are extremeley pinned down by genetics, because the complicated map from underlying brain stuff to personality is chaotic.